The present invention relates to linear motors and, more particularly, the invention relates to a stator assembly for such a motor.
Linear motors are well known generally for a considerable length of time; also, linear motors have been constructed in a variety of configurations; there are d-c motors, and synchronous as well as asynchronous a.c. motors. Generally speaking, a linear motor includes a stator arranged in, or along, a line, and does not have an annular configuration. The moving armature is correspondingly constructed; it does not rotate.
The linear motor provides, generally, a conversion of electrical energy into translatory mechanical energy. A three-phase motor, for example, has three separate energizing systems, being suitably arranged in the stator body. The armature may consist of a rail element made of copper or aluminum, i.e., of a good electrical conductor to establish an asynchronous motor. Alternatively, the armature may be comprised of a permanent magnetic body for establishing a synchronous motor. A certain variety of linear motors includes coils on the armature.
Linear motors are used for a variety of purposes, such as "people movers," as drive in the conveyor and transport art, for example, for baggage handling, or for moving freight, generally. Linear motors are also used in mining, for operating cranes, drag equipment, slides in machine tools, operation of gates, etc. The length of such a motor depends greatly on its use and on the path length to be traversed. The stator coils and winding, i.e., its wiring, can be, and usually has been, placed inside the stator core body. Thus, assembling of the coil is a significant part of the stator installation and is very costly for long stators. Particularly, the known stator installations require highly skilled persons.
In a more specific example, consider a linear motor constructed for driving any kind of transportation equipment, such as a vehicle. The stator is to be installed along the track on which the vehicle runs. Such a track is rarely very straight. Rather, the transport path and track may have many curves. Upon installing the stator, many parts are assembled along that track and fastened to a carrier or the like. The individual stator parts are separated from each other by gaps for reasons of tolerances. These gaps may become quite large in curves of the track. Moreover, one will have to provide for larger gaps, the longer the stator parts are, and these parts are quite large in order to reduce on-site installation time. The resulting gaps inevitably interfere with the magnetic flux distribution of the motor. Moreover, if the gaps are irregularly wide (as one must expect), the interference with the flux distribution is correspondingly an irregular one. To compensate at least these irregularities, one has to adjust the position of the stator parts to each other at the installation site which is quite a time-consuming procedure.